Locking means for fluid motors



May 31, 1938. E. c. s. CLENCH 1 I I 'LOCKINGMEANS FORIFLUID'MQTORS Original Filed Au 29, 19s5 'atented May 3 1, 1938 UNITED STATES PATENT OFFICE Spa, England, assignor to Automotive Products Company Limit ed, London, England Original application August 29, 1935, Serial No. 38,460. Divided and this application May'19, 1936, Serial No. 80,643. In Great Britain Sep-' tember 5, 1934 7 Claims.

This invention relates to remote control apparatus of the kind in which liquid pressure in one )1 more pipe lines serves as the medium for transmitting movement from a master cylinder to a slave cylinder unit.

It is the object of the present invention to provide an improved system and constructional form of motor cylinder unit in which means are incorporated for preventing the slave cylinder setting from being altered by forces applied thereto other than the pressure liquid received as a result of the master cylinder being actuated.

The present invention providesa liquid pressure remote control system having a device for mechanically locking the setting of the member actuated by the motor cylinder unit, said system being characterized by the fact that said locking device is automatically released concurrently with the passage of pressure liquid from the master cylinder into the motor cylinder, said release being effected in the motor cylinder itself or in an auxiliary cylinder supplied in common therewith from the master cylinder. The invention further provides an improved system which is characterized in that the locking device is effectual at any setting of the slave cylinder unit, and is automatically released by pressure liquid forced into the slave cylinder unit by the master cylinder.

As a further feature the invention provides a double-acting motor cylinder unit for a two pipe line remote control system, the cylinder of said unit being divided by a piston into two. compartments, each of which latter is bounded by a pressure-responsive member serving, when liquid is forced into either of the working compartments,

to release automatically a one-way locking device and thus permit relative movement of the cylinder and piston under the influence of said liquid.

The motor cylinder unit may be provided with a locking device which acts as a one-way clutch, and in a particular example as applied to a double-acting slave cylinder, a pair of one-way locking devices are provided and are adapted to work in opposition, thus in effect locking the setting of the motor cylinder unit against unwanted movement in both directions.

The invention is illustrated in the accompany- ,ing drawing in which:- i Figure 1 is a part sectional plan showing a motor cylinder" unit connected with a master cylinder arrangement as described in our copending application Serial No. 38,460; and

Figure 2 is a fragmentary sectional plan of the I 4 l4, the position of which is governed by an arm l6 connected with an operating member indil cated at 25 and carried by a spindle 22. Thus when the member 25 is moved to the right the piston element I4 passes to the left expelling liquid under pressure from the master cylinder l2 through the pipe line 48 to the remotely placed motor cylinder 50. At the same time the pipe line 49 serves to transmit liquid expelled from the right hand side of the motor cylinder back to the other master cylinder i3, within which, of course, the piston element I4 is receding. 1

The construction of motor cylinder unit illustrated as an example of the. present invention comprises a substantially tubular cylinder 5| having extending coaxially therethrough a rod 52 serving as the operated element and provided with a piston 53 fitted with rubber cups 54 and 55, said piston being held firmly upon the rod 52 by means of a pin 56. It is important that locking means should be provided for the rod 52 so that forces applied thereto, other than operating forces, will not be able to alter the setting of said rod 52, and for'this purpose a locking means is provided at each end of the motor cylinder unit 50. The left hand locking means is shown in section in Figure 1, but it will be understood that 3 the right hand locking means is exactly similar in construction, although it is, of course, adapted to i work in the opposite direction. The working space 58 is bounded by an auxiliary cup washer or piston 59 which bears against a sleeve BD'haVing a circumferential series of perforations for the guidance of a corresponding number of balls 6|. These balls arenormally urged by a spring 65 into contact with the interior frusto-conical surface of a wedge ring 62, which is held in position by means of a gland nut 63 and which serves to support a stop washer 64 cooperating with a cir--- cumferential flange formed upon the sleeve 60. It will be seen that any tendency to move the rod 52 to the right will be counteracted by the wedging of the balls of theleft hand locking means.

' while a similartendency actingtowards the left will be prevented from moving the rod 52 by means of the locking balls at the right hand end of the motor cylinder 50. When, however, the

rod 52 is to be moved hydraulically by the operating lever 25, pressure fluid entering say the left hand working space .58 first presses up slightly the auxiliary cup washer 59 thus moving the sleeve 60 to the position shown in Figure 2 and disengaging the balls 6| from the ring 62.

The hydraulic pressure thereafter acts upon the piston 53, thus moving the rod 52 to the right. 'When the requisite movement has been made the spring once more locks the balls 6| against the ring 62.

It should also be understood that the looking device shown in Figures 1 and 2 can equally well be incorporated with a closed liquid pressure system, that is, one in which the pipe lines are not relieved of pressure between operations.

This application is a division of application filed August 29, 1935, Serial No. 38,460.

What I claim is:

1. For a liquid pressure remote control system, a motor unit comprising a cylinder, a main piston dividing said cylinder into two working spaces, an auxiliary piston within said cylinder,-locking means associated with the auxiliary piston and adapted to lock the piston rod relatively to the cylinder in any position, said auxiliary piston first being moved by liquid forced into the cylinder, thus releasing the locking means and enabling the main piston to move under the influence of the liquid.

2. For a liquid pressure remote control system, a motor unit comprising a cylinder, a main piston dividing'said cylinder into two working spaces, an auxiliary piston in each of said spaces, and a pair of opposing one-way locking devices each adapted to be rendered inoperative by one of the auxiliary pistons when liquid under pressure enters the corresponding working space, thus enabling the main piston to be moved by said liquid.

3. For a liquid pressure remote control system, a motor unit comprising a cylinder, a-main piston dividing said cylinder into two working spaces, 'an auxiliary piston bounding each of said spaces, and a one-way wedge device associated with each of the auxiliary pistons, each of said wedge devices comprising a locking element engaged within a chamber bounded by axially converging walls carried by the cylinder and piston rod respectively, anda spring which urges the locking element towards a jamming position while the auxiliary piston is arranged to press the locking element in the reverse direction, so as to release the wedge device when liquid is forced under pressure intothatworking space bounded by the respective auxiliary piston.

4. For aliquid pressure remote control system a motor unit comprising a cylinder, a main piston dividing said cylinder into two working spaces,

a piston rod extending coaxially through the cyI inder and attached to the main piston, an aux iliary piston fitted at each end of the cylinde and formed with a circumferential series of hole: balls located in the holes and engaging the pis ton rod at their inner parts, a tapering wall upo: the cylinder which wall is engaged by the oute parts of the'balls, and a spring urging the am: iliary piston so that the balls tend to jam be tween the tapering wall and the piston rod.

5. For a liquid pressure remote control systerr a motor unit comprising a cylinder, a main pis ton dividing the cylinder into two working space: a piston rod carrying the piston, and lockim means disposed within the cylinder, said look ing means consisting of two separate one-wa: frictional wedge devices in which the resistanc1 to .movement increases as the external force tending to overcome the locking increases, S8.i( wedge devices being arranged in opposition anc acting between the cylinder and the piston roc at any setting of said piston rod, each of saiC wedge devices being released by the entry 01 liquid under pressure into that side of the cylinder causing movement of the piston rod in the direction normally prevented by said wedge device.

6. For a liquid pressure remote control system, a motor unit comprising a cylinder, a main piston within said cylinder, an, auxiliary piston bounding the working space within said cylinder and locking means for preventing movement of the main piston, said locking means being of the form in which the locking effect, which takes place automatically at any position of the main piston, increases as the external force tending to overcome said locking effect increases, and the locking means being connected with the auxiliary piston so that movement of said auxiliary piston under the action of liquid pressure withi the cylinder releases the locking means. '7. For a liquid pressure remote control system, a motor unit comprising a cylinder, a main piston within said cylinder, an auxiliary piston bounding the working space within said cylinder, and locking means for preventing movement of the main piston, said locking means comprising a one-way wedge device in which the locking effect, which takes place automatically at any position of themain piston, increases as the external force tending to overcome said locking efiect increases, and said locking means being connected with the auxiliary piston" so that movement of said auxiliary piston under the action of liquid pressure within the cylinder releases the locking means.

' EDWARD CLAUDE SHAKESPEARE CLENCH. 

